The in situ treatment of liquids (including sludges and slurries) has been a long-standing problem. For example, the in situ neutralization of acidic and caustic liquids has been a long-standing problem in the chemical and oil processing industries. The present invention relates to a new method and apparatus for treating liquids (including without limitation, slurries and sludges), e.g. neutralizing acidic and caustic liquids, in a tank. More particularly, this invention pertains to the use of a unique and controlled injection method and apparatus to increase the reaction mixing between a treating solution, e.g. a neutralizing solution, and the liquid being treated, e.g. undergoing neutralization. In the preferred embodiment, radial and tangential injection wands (sometimes also called lances) are moved into a tank containing a liquid and a treating solution is injected through the injection wands into the tank. This method and apparatus permits one to take advantage of the increased mixing caused by the injection of the treating solution through the injection wands and into the tank.
In another preferred embodiment of the present invention, injection wands (or lances) are inserted at approximately the same location, e.g. a manway cover plate, into a tank containing a liquid to be treated. A treating solution is injected through the injection wands into the tank. Each injection wand is attached to a joint that allows for the angle between each wand relative to the tank bottom to be altered and/or for the angle between each wand and the wall of the tank to be altered. This embodiment also permits one to take advantage of the increased mixing caused by the injection of the treating solution through the injection wands and into the tank. The present invention may be applied in a wide range of situations, e.g. chemical neutralization or other treatment of tank contents. One example is the treatment of sour liquid, i.e., liquid that is contaminated with hydrogen sulfide (H.sub.2 S). Hydrogen sulfide is generated in numerous areas, e.g. oil reservoirs, oil refineries, chemical plants, and waste treatment facilities, including landfills and sanitary waste facilities. The hydrogen sulfide makes liquid "sour" and highly toxic. Any suitable treating solution, e.g. sodium hypochlorite (NaOCl), can be used to treat the sour liquid in the present invention.
The present invention is not limited to the neutralization of sour liquid, and those of skill in the art will recognize many other applications of the present invention, e.g. acid can be injected to neutralize caustics, amines can be injected to treat other sulfide contaminated materials, etc.
It is believed that the present invention can be described as a way to create and take advantage of the Coriolis force, an effect created by high velocity injection through the injection wands. In simplistic terms, Coriolis forces arise when there is radial movement of mass from one point on a rotating plane to a second point. This movement results in a change of the peripheral velocity of the mass and increases the acceleration of the mass. The acceleration of mass generates a force in the plane of rotation and perpendicular to the instantaneous radial movement. The Coriolis phenomenon can be found in nature and is associated with the earth's rotation. For example, the Coriolis force is responsible for the spinning of liquid as it is drained from an ordinary bathroom sink. In the Northern Hemisphere, the Coriolis force causes fluids in motion to spin in a clockwise direction.
The present invention is an improvement over the prior art. For example, U.S. Pat. No. 4,818,412 teaches an apparatus and process for feeding hypochlorite solution to a tank to treat sour water. However, this patent does not teach how the hypochlorite solution can be added to the sour water in a manner that creates and takes advantage of the increased reaction mixing between hydrogen sulfide (the contaminant) and the hypochlorite solution (the treating solution).
The preferred embodiment of the present invention teaches the use of a unique controlled injection method and apparatus using radial and tangential injection wands (or lances) that are inserted into a tank containing a liquid requiring treatment, injecting treating solution through radial injection wands to stir the liquid within the tank in a clockwise manner, and injecting treating solution through tangential injection wands to increase the reaction mixing between the liquid being treated and the treating solution, and monitoring and controlling the reaction process, thereby providing benefits that have never been attained before.
The other preferred embodiment of the present invention teaches the use of a unique controlled injection method and apparatus using injection wands (or lances) to inject treating solution into the tank to stir the liquid within the tank in a clockwise manner, and injecting treating solution into the tank to increase the reaction mixing between the liquid being treated and the treating solution, and monitoring and controlling the reaction process, thereby providing benefits that have never been attained before.
The present invention also teaches the use of unique nozzle apparatuses that promote the reaction mixing and the sweeping of particles from the bottom and walls of the tank so that the particles can become suspended in the liquid being treated and be removed from and/or treated in the tank.